Color selection scheme for digital video watermarking

• US 20050069168A1
• Filed: 09/29/2003
• Published: 03/31/2005
• Est. Priority Date: 09/29/2003
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Inventors: Zarrabizadeh, Mohammad Hossein
• Granted Patent: US 7,630,509 B2
• Time in Patent Office: Days
• US Class Current: 382/100
• CPC Class Codes: G06T 1/0028 Adaptive watermarking, e.g. Human Visual System [HVS]-based watermarking
• CPC Class Codes: G06T 2201/0051 Embedding of the watermark in the spatial domain
• CPC Class Codes: G06T 2201/0061 Embedding of the watermark in each block of the image, e.g. segmented watermarking
• CPC Class Codes: G06T 2201/0202 whereby the quality of watermarked images is measured; Measuring quality or performance of watermarking methods; Balancing between quality and robustness
• CPC Class Codes: H04N 1/32144 embedded in the image data, i.e. enclosed or integrated in the image, e.g. watermark, super-imposed logo or stamp
• CPC Class Codes: H04N 1/32309 in colour image data
• CPC Class Codes: H04N 2201/3233 of authentication information, e.g. digital signature, watermark
• CPC Class Codes: H04N 2201/327 which are undetectable to the naked eye, e.g. embedded codes

Abstract

Determining a chrominance portion to be watermarked employs a perception-based table that indicates for various pixel values which of the chrominance portions, if any, should be selected for watermarking. Only the Y, U, and V values of a pixel are needed to access the table and determine which chrominance portion should be selected. However, the table may be represented such that it may be accessed using only R, G, and B values. The table may be modified so that it may indicate which of U or V should be selected, or that neither should be selected, indicating that this pixel should not be watermarked at all. Advantageously, the table may be simplified by employing some processing, because a large section of the table may be replaced by a simple test on the pixel values, e.g., U<128, to determine the selected chrominance portion.

Claims

1. A method for selecting a chrominance portion of a pixel to be watermarked, said selecting step employing a perception-based table that indicates for each of at least a plurality of possible pixels in a colorspace which, if any, of the chrominance portions should be selected for watermarking.

2. The invention as defined in claim 1 wherein said perception-based table indicates for each entry therein whether to watermark only a first chrominance portion or only a second chrominance portion.

3. The invention as defined in claim 1 wherein said perception-based table indicates for each entry therein whether to watermark a first chrominance portion, a second chrominance portion, or not to watermark at all.

4. The invention as defined in claim 1 wherein said perception-based table is in computer readable form.

5. The invention as defined in claim 1 wherein said perception-based table divides an entire colorspace into regions, at least one of said possible pixels within each said region, and said perception-based table supplies an indication for said pixel based on which region of said perception-based table said pixel falls.

6. The invention as defined in claim 1 wherein said pixel is part of a digital video bitstream represented in YUV format and wherein said perception-based table indicates for any pixel to watermark U or V as a function of the Y, U, and V values of said pixel.

7. The invention as defined in claim 1 wherein said pixel is part of a digital video bitstream represented in YUV format, and wherein said selecting step is performed using only said YUV formatted digital bitstream directly and no other version of said digital bitstream formatted in any other format.

8. The invention as defined in claim 1 wherein said pixel is part of a digital video bitstream represented using a first colorspace type representation, and wherein, said selecting step is performed using only a digital bitstream formatted in said first colorspace type representation directly and other colorspace type representation.

9. The invention as defined in claim 1 wherein said pixel is a decimated pixel derived from an original digital video bitstream.

10. The invention as defined in claim 1 wherein said pixel is a decimated pixel derived from an original digital video bitstream represented in YUV format,

11. The invention as defined in claim 1 wherein said pixel is a quantized pixel derived from an original digital video bitstream.

12. The invention as defined in claim 1 wherein said pixel is a quantized pixel derived from an original digital video bitstream represented in YUV format,

13. The invention as defined in claim 1 wherein said perception-based table contains information to indicate which, if any, of the chrominance portions should be selected for watermarking for each pixel value of the entirety of said colorspace.

14. The invention as defined in claim 1 wherein said perception-based table contains information to indicate which, if any, of the chrominance portions should be selected for watermarking for each possible pixel of only a prescribed portion of said colorspace, and wherein said selecting step further comprises the step of determining that a pixel is within said prescribed portion of said colorspace for which said perception-based table contains information.

15. The invention as defined in claim 1 wherein said perception-based table contains information to indicate which, if any, of the chrominance portions should be selected for watermarking for each possible pixel of only a portion of said colorspace, and wherein said method further comprises the steps of:

determining that a pixel is not within said portion of said colorspace for which said perception-based table contains information; and

determining which, if any, of the chrominance portions should be selected for watermarking for said pixel, as a computed function of at least one value of said pixel.

16. The invention as defined in claim 1 wherein a chrominance portion of said pixel is watermarked by having its value changed to represent the conveyance of additional data other than the original value of said chrominance portion.

17. Apparatus for supplying an indication as to which chrominance portion of a pixel of a video signal, if any, is better suited to be altered so as to carry additional watermark information, said apparatus comprising a perception-based table in a computer readable media for at least a portion of the possible pixel colorspace, said table specifying for pixels that are within said portion of said colorspace the chrominance portion to be indicated by said apparatus.

18. The invention as defined in claim 17 further comprising a computation unit for indicating for a pixel that is not within said portion of said colorspace which chrominance portion is to be indicated based on at least a value of one of said chrominance portions of said pixel.

19. The invention as defined in claim 17 wherein said chrominance portion is better suited to be altered when altering said chrominance portion will produce less, if any, visible artifact than altering any other chrominance portion of said pixel.

20. A method for selecting a chrominance portion of a pixel to be watermarked, said selecting step employing a perception-based table that indicates for each of at least a plurality of possible pixels in a colorspace which, if any, of the chrominance portions most likely had watermark data added thereto.

21. Apparatus for selecting a chrominance portion of a pixel to be watermarked, said apparatus comprising a perception-based table in a computer readable medium that indicates for each of at least a plurality of possible pixels in at least a portion of a colorspace which, if any, of the chrominance portions would be least likely to introduce a visible artifact should watermark data be added thereto.

22. Apparatus for selecting a chrominance portion of a pixel to be watermarked, said apparatus comprising:

a computer readable store containing a perception-based table that indicates for each of at least a plurality of possible pixels in at least a portion of a colorspace which, if any, of the chrominance portions should be selected for watermarking; and

means for accessing said store to determine which chrominance portion, if any, to select, when said pixel is one of said pixels in said portion of said colorspace.

23. The invention as defined in claim 22 further comprising means for computing as a function of a least one value of said pixel which, if any, of the chrominance portions should be selected for watermarking, said means for computing operating only when said pixel is not one of said pixels in said portion of said colorspace.

24. Apparatus for selecting a chrominance portion of a pixel to be watermarked, said apparatus comprising:

a computer readable store containing a perception-based table that indicates for each of at least a plurality of possible pixels in at least a portion of a colorspace which, if any, of the chrominance portions most likely had watermarking data added thereto; and

means for accessing said store to determine which chrominance portion, if any, to select, when said pixel is one of said pixels in said portion of said colorspace